1. Field of the Invention
The present invention relates to proteins, to a method of obtaining proteins, to food products, and to a method of processing food products. In another aspect, the present invention relates to proteins having high solubility, to a method of obtaining highly soluble proteins, to a method of increasing protein yield, to food products made from highly soluble proteins, and to a method of processing food products. In yet another aspect, the present invention relates to highly soluble food grade plant proteins, to a method of obtaining highly soluble food grade plant proteins utilizing antioxidants, to a method of increasing the protein yield utilizing antioxidants, to food products made from such highly soluble food grade plant proteins, and to a method of processing food products utilizing antioxidants.
2. Description of the Related Art
Proteins find utility in a broad range of applications in the food processing industry for both human and animal consumption. For example, for human consumption vegetable proteins are used in the making of non-dairy whip topping, non-dairy creamer, meat analogues, cheese analogues, seafood analogues, tofu, extruded snack items, beverages, confections, soups, pastas, breads, as well as infant formula, as well as a whole host of processed meat products.
Food grade soybean proteins have been available for many years, and are readily extracted from defatted flour by water at pH 6.6, but the proteins obtained by the prior art methods are only slightly soluble at this pH after isolation by acid precipitation.
Unfortunately, in order to be applicable for use in most food systems, a protein must have good solubility in water or mildly acidic solutions. Therefore, attempts have been made in the prior art to study and to improve the solubility of soybean protein isolates.
U.S. Pat. No. 4,464,296, issued Aug. 7, 1984 to Jacks et al. discloses a method of improving the solubility of dry protein in aqueous or acidic media after treatment with a concentrated (30%) hydrogen peroxide solution. In this process, the protein is mixed with hydrogen peroxide and the mixture centrifuged for sufficient time to effect clarification. Unfortunately, this process suffers from the limitation of having to remove the concentrated hydrogen peroxide as it renders the protein unsuitable for food applications. Thus, the hydrogen peroxide is removed by dialyzing the supernatant against water containing sufficient catalase to remove the hydrogen peroxide. The protein is then freeze dried.
U.S. Pat. No. 4,474,694, issued Oct. 2, 1984 to Coco et al., discloses a process for making a modified protein for use as an adhesive binder. The method includes treating defatted soybean flakes with an alkaline solution to solubilize the protein. Next, the protein extract is then separated from the alkali insoluble solids by filtration or centrifugation. Next, the soy protein is treated with a reducing agent, followed by treatment with a carboxylic acid anhydride. The patent states that "[t]his treatment step is important in that the use of a reducing agent with modification by reaction with the carboxylic acid anhydride results in a modified protein material which has unusual rheological characteristics when employed as an adhesive binder in a pigment containing coating composition.
U.S. Pat. No. 4,551,274, issued Nov. 5, 1985 to Shen discloses as prior art that chemical reducing agents may be utilized to increase the solubility of vegetable protein material, but are somewhat ineffective because of the relative inaccessibility of the protein disulfide bonds to the reducing agents. Additionally, chemical reducing agents will many times render the protein product unsuitable for food applications. As an improvement, the '274 patent discloses the electrolytic treatment of vegetable protein to reduce the disulfide bonds to provide a dissociated protein material which has an improved degree of solubility. This electrolytic process suffers from the limitation of requiring apparatus to carry out the electrolysis.
Typical protein products derived from protein flour or flakes includes protein isolates and protein concentrates. The protein yield is generally the percentage of the protein in the flour or flakes that is recovered in the protein product. As the protein yield effects the economics of protein processing, higher protein yields are always desirable.
Thus, there is a need in the art for an improved food grade protein not suffering from the deficiencies of the prior art proteins.
There is another need in the art for a highly soluble food grade protein not suffering from the limitations of the prior art.
There is yet another need in the art for a method for obtaining highly soluble proteins.
There is still another need in the art for a method of obtaining highly soluble food grade proteins.
There is even another need in the art for food products containing highly soluble food grade proteins.
There is still yet another need in the art for a method of processing food products utilizing highly soluble food grade proteins.
There is still yet even another need in the art for a method of increasing the overall protein yield of protein processing methods.
These and additional needs of the art will become readily apparent to those of skill in the art upon review of this patent specification.